1. Field of the Invention
The present invention relates to a storage unit connected to a host apparatus, such as a computer, for accessing a storage medium according to a direction from the host apparatus, a condition monitoring program product executed in the host apparatus to which the storage unit is connected for configuring in the host apparatus a condition monitor that monitors conditions of the storage unit, and a condition monitoring program storage medium storing the condition monitoring program.
2. Description of the Related Art
Storage units for accessing storage media have been widely used as computer peripherals.
As is often the case, an abnormal condition in such a storage unit, an optical disk unit, for example, cannot be found until it results in a data failure in the process of practically using the optical disk unit, the optical disk unit becomes unrecognizable to the host computer to which it is connected, or other abnormal symptoms such as unusual noise or abnormal lighting of an LED indicator that are obvious to a user occur. Although the abnormal condition can be prevented at the time of early maintenance. However, when the user notices the abnormal condition, it may have resulted in a fatal failure. If such a failure occurs and the user sends the unit for repair or buys a new one, he or she does so without identifying which part of the unit has failed or what kind of failure has occurred. For example, if the optical disk unit has no failure but instead an optical disk loaded in the optical disk unit is defective, the user may misconceive that the optical disk unit is defective and sends the disk unit for repair or buys a new one. Or, if the nature of a failure is such that repairing the unit is more expensive than buying a new one but the user does not know it, he or she may send it for repair. Conversely, even if the failure can be easily remedied, the user may buy a new, expensive unit. If the user could know the nature of the failure, he or she would be able to avoid such improper or unnecessary actions.
A variety of approaches to detecting abnormal conditions in storage unit have been proposed. For example, Japanese Patent Laid-Open Publication No. 10-134527 discloses a disk reproduction apparatus that detects certain abnormal conditions and generates an alarm. However, the technology proposed in the application defines a single criterion for determining abnormal conditions, ranging from a minor to serious one, in the apparatus. The technology proposed in that application only increases the number of aspects of abnormal conditions, such as data failure, abnormal noise, and abnormal lighting of LED indicators, that are obvious to a user by one. It cannot report abnormal signs to the user in an earlier stage or incorporate in the criterion user' concept as to whether he or she treats it as a failure.
Japanese Patent Laid-Open Publication No. 6-51915 discloses a method in which an operation history and information about frequency of retries performed in a disk unit are recorded and, when a predetermined value is exceeded, a user is notified that the lifetime of the unit has expired.
Like the technology described earlier, this method defines a criterion for determining whether the lifetime has expired and indicates expiration of the lifetime. It also cannot report abnormal signs to the user in an earlier stage or incorporate in the criterion user's concept as to whether he or she treats it as a failure.
Japanese Patent Laid-Open Publication No. 11-353682 discloses a method in which a user is prompted to perform head cleaning when certain abnormal conditions occur.
Prompting the user to perform head cleaning when abnormal conditions occur may be one effective method. However, it would be more effective to prompt the user to periodically perform head cleaning before any abnormal conditions occur in order to avoid such conditions.
An optical disk unit does not necessarily remain connected to a particular computer until it is discarded from the starting point of using the optical disk unit, or management information held in a particular computer that controls the optical disk unit may be reset through the replacement of its hard disk, for example. If the computer is replaced with a new one and the optical disk unit connected to the old computer is connected to the new one just before the time of inspiring a cleaning, a counter counting intervals for prompting the user to perform head cleaning is initialized and therefore no message for prompting the user to perform head cleaning is provided until a long period of time expires after the connection of new computer. As a result, head cleaning is not performed, resulting in abnormal conditions.
A method is described in Japanese Patent Laid-Open Publication No. 4-165538 in which retries performed in a unit are counted at predetermined intervals, the number of retries is compared with criteria, and degradation determined from the comparison is reported to a user. However, a user receiving the report cannot know what to do about the problem and may uninformedly send the unit for repair.
In addition, in order to always properly manage the conditions of a storage unit, it is required to exactly know how much time has elapsed since the storage unit was brought into use. Storing the date on which the storage unit was brought into use in a computer to which the storage unit is connected may be one effective method for keeping track of the elapsed time. However, this information alone cannot show the exact elapsed time. This is because the computer to which the storage unit is connected can be updated or data storage means (a hard disk drive, for example) within the computer can be updated when it fails and, as a result, it can become impossible to exactly know the date on which the storage unit was first brought into use. A system may be provided in which customer information is registered and a date on which the storage unit was brought into use is stored as an item of the customer information. However, users do not always register themselves with the system. The system therefore is insufficient in terms of keeping track of the elapsed time. None of the above-described applications describe an approach to keeping track of time elapsing since a storage unit was brought into use.